Neisseria meningitidis capsular polysaccharide antigen (serogroups A, C, W, Y) (null)

The Neisseria meningitidis capsular polysaccharide antigens of serogroups A, C, W, and Y are high-molecular-weight carbohydrate polymers forming the outer capsule of the bacterium Neisseria meningitidis. These capsules are composed of repeating sugar units unique to each serogroup (A: (α1→6)-linked N-acetylmannosamine phosphate; C, W, Y: sialic acid-containing polysaccharides with serogroup-specific linkages) and serve as the primary basis for serogroup classification[7][10]. They protect the bacteria from host immune responses by inhibiting phagocytosis and complement-mediated lysis[7][9]. Vaccines targeting these antigens, especially when conjugated to carrier proteins, induce production of protective antibodies that mediate complement-dependent killing and opsonization, providing effective immunization against invasive meningococcal disease caused by these serogroups[7][3][10]. The measurement of serum antibodies against these polysaccharides can serve as a biomarker of vaccine-induced protection[3]. These antigens are not individual proteins or enzymes but rather polysaccharide structures, so they fall outside classical "drug targets" like receptors or enzymes, but they are the canonical molecular targets for several widely used vaccines, and measurement of antibody responses to them is a standard efficacy biomarker[3][9][10].

Other names

Meningococcal capsular polysaccharide (A, C, W, Y)MenA-C-W-Y antigenMeningococcal group A, C, W, Y antigens

Induction of antibody production leading to complement-mediated bacterial killing (serum bactericidal activity) Prevention of bacterial invasion by antibody-mediated opsonization